Track for ground effect machines

ABSTRACT

A track for guided ground effect machines, the track having a machine-supporting portion and a guidance rib and including a passage arranged within the thickness of the said rib to cause the space covering the top of the said rib to be in communication through the said passage with a space defined by the machinesupporting portion of the track and which communicates with the outside atmosphere, whereby redundant lifting forces acting on the machine are substantially avoided.

United States Patent Du Merle [4 1 Apr. 25, 1972 1 41 TRACK FOR GROUNDEFFECT 1 1 References Cited MACHINES UNITED STATES PATENTS 1 lnventorr yCharles Marie J p Du Merle, 3,048,127 8/1962 Oberpaul ..10s/145Par1s,France 3,096,728 7/1963 Y Amann ....104/134 3,583,327 6/1971Arndt.... ..104/120 [73] Asslgnee' Swim France 3,233,559 2/1966 Smith..104/23 FS 221 Filed: Nov. 12, 1970 Primary Examiner-Arthur L. La Point[21] App, 88639 Assistant Examiner-D. W. Keen Attrney-Stevens, Davis,Miller & Mosher [30] Foreign Application Priority Data ABSTRACT Nov. 15,1969 France ..6939364 A track for guided ground effect machines, thetrack havinga 52 us. 01. ..104/23 rs, 104/134, 104/120,machine-suppflfling Portion and a guidance rib and including 105 [/14 apassage arranged within the thickness of the said rib to cause 51 1111.C1. ..B6lb 13/08, EOlb /08 the Space covering the P of the Said he incommunica- [58] Field olSearch ..104/23 FS, 134, 118,120,148 LM; throughthe said p ge w t a space defined by the /141, machine-supportingportion of the track and which communicates with the outside atmosphere,whereby redundant lifting forces acting on the machine are substantiallyavoided.

5 Claims, 3 Drawing Figures PATENTEDAPRZS m2 3658.010

SHEET 1 [1F 2 TRACK FOR GROUND EFFECT MACHINES This invention relates toa track for ground effect machines.

It is known, in a guided ground effect machine employing a track thecross-section of which has, for example, the shape of an inverted T, toprovide the machine with a longitudinal slot which cooperates with theprojecting central guidance rib through the intermediary of cushions ofpressurised fluid located on either side of the said rib. The leaksissuing from these cushions into the upper portion of the slot lead to astate of overpressure within the latter, the result of this on thestructure of the machine giving rise to an increase in the lift effect.This increase entails no drawback and indeed, rather, is advantageous atlow speeds, but it will be seen hereinafter that this is no longer thecase at high speeds.

When the dynamic pressure becomes greater than the pressure of thecushion, such entry of fluid as may occur through the front end of thecushions providing lift does not entail any increase in the pressure ofthese cushions, which are always kept in balance by the weight of themachine, but it merely entails a slight lifting of the machine, alifting movement limited by the resulting increase in the leakage fromthe supporting cushions via their free margin in the direction of theoutside atmosphere on the side opposite the guidance rib.

This is not the case with cushions providing guidance, whose front wallsmay likewise absorb dynamic pressure, because these cushions are set upopposite each other and because their distance away from the centralguidance rib, a distance determined by the invariable width of thelongitudinal slot appertaining to the machine, is not able to increaseas is the case with cushions providing lift. This therefore entails inthe said slot an increase in pressure which, acting on the structure ofthe machine (which is closed in at this spot), brings about a redundantlifting force which increases as the speed does, and is liable to giverise to major disadvantages at very high velocities.

In another connection the leaks issuing from these guidance cushions inthe vicinity of the machine-supporting portion of the track are added tothe leaks coming from the lift-providing cushions along the saidmachine-supporting portion, more especially at the re-entrant angleswhich exist at the junction of the central rib with themachine-supporting portion of the track. This phenomenon gives rise to adiffering rate of wear on the inner and outer confining walls of thecushions providing lift. This may be remedied, for example, by asuitable adjustment of the flexibility of the said confining walls, butit may be important to eliminate the cause of this.

In order to minimize these drawbacks, it is therefore important toeliminate the increase in pressure within the slot and, in addition, theincrease in pressure which occurs at the re-entrant angle of the track,this being effected by making the slot communicate with the outsideatmosphere.

The solution, which consists in providing a passage through the machineitself, can only be practised with difficulty, both because of thebulkiness of the ducts that would be necessary for this purpose andbecause of the awkwardness of making an appropriate choice as to theareas where these ducts should have port.

The solution finally selected and forming the subject of the presentinvention consists in providing the guidance rib or ribs of the trackwith means which render possible communication between the existing slotunderneath the machine and a space located beneath themachine-supporting portion of track, the said space being connected tothe outside surrounding atmosphere.

According to the invention, the means in question comprise a passagearranged inside the guidance rib and bounded by the substantiallyvertical walls of the said rib.

According to a further feature of the invention, it is possible toarrange in the central rib orifices which are intended to take upover-pressures close to the re-entrant angles existing at the junctionof the central guidance rib with the machine-supporting portion of thetrack.

The following description relating to the accompanying drawings, whichare given by way of non limitative example, will indicate how theinvention may be carried into practice.

In the drawings FIG. 1 is a view of a cross-section through a firstembodiment according to the 10;

FIG. 2 is a view in section taken along the line 11-1! in FIG.

FIG. 3 is a view of a modification of one detail in FIG. 1.

Referring to FIGS. 1 and 2, here there is shown a machine 1 whichcooperates with the machine-supporting portions 2a, 2b and with theguidance walls 20, 2d of a track, on the one hand by means of cushions3a, 3b which provide lift, and on the other hand by means of cushions3c, 3d, which provide guidance, the said track possessing acrosssection, according to the embodiment illustrated in these figures,substantially'in the form of an inverted T.

According to the invention, the central rib providing guidance is madeup of the walls 2c and 2d, which will preferably be rigid, for examplebeing of metal and substantially parallel, and which between themdelimit at least one passage 20 making it possible to link thelongitudinal slot 4 (arranged within the structure of the machine) witha space 5 located beneath the machine-supporting portion of track andcommunicating with the outside surrounding atmosphere.

The walls 2c and 2 d pass down through the machine-supporting portion oftrack made up of the structures 20a and 20b, which are, for example,composed of concrete. The walls 2c and 2d terminate in upper margins 20cand 20d which are preferably curved over so as to obviate deteriorationof the confining walls appertaining to the cushions 3c and 3d.

The hollow central rib should have an unyielding structure able towithstand lateral stresses connected with guidance and, if so required,also the longitudinal stresses due to the propulsion of the machine inthe case in which, for example, the central rib constitutes the armatureof a linear-motor system of propulsion in which the coil is carried bythe machine, or the stresses due to braking if the machine is equippedwith jaw-type brakes which squeeze tight against the central guidancerib and in the latter case the stresses associated with bilateralcompression or crushing as exerted by the jaws. The structural parts aredisposed in such a manner as not to offer opposition to flows of fluidtowards the space 5. With this aim in view, it may, for example, bepossible to arrange diaphragms or dividing plates 6, preferably of metaland provided with relieving holes 7, in a vertical setting at intervalsbetween the walls 20 and 2d and at right angles to the latter, to whichthey are attached, for example, by means of bolts or rivets (not shown).In order to resist stresses in compression, more especially in the areassubjected to braking action, the diaphragms 6 may, for example, belinked together by means of struts 8 kept substantially parallel to eachother and rendered rigid with the walls 2c and 2d by means of bolts orrivets (not shown).

The firm connection of the metal central rib to the machinesupportingportions of track made of concrete is effected, for example, by means ofstruts 9 which include a threaded part for cooperation with nuts in thiscase, the adjustment of the transverse alignment of the track on itssupports 11 is effected by means of devices arranged laterally along themachine-supporting portion of track and the supports, for examplescrew-jacks 10a, 10b.

It is possible to envisage a case in which, with the struts 9 passingthrough the central rib without rendering the latter rigid with themachine-supporting portions of track, the connection of the rib to themachine-supporting portions is effected, for example, by means of asystem of angle-plates or of angle-bars 12 which include bolts 120, thesaid angle-plates being fitted with means to provide transverseadjustment, such as, for example, screw-actuated devices (not shown) inorder to carry out alignment of the track without affecting the concretestructures 20a, 20b.

According to a preferred example, the excess fluid due to leaks fromunder the cushions providing lift and those providing guidance,adjacently to the junction of the walls 2a, 2b, 2c and 2d, may be venteddownward to the space 5 by way of orifices 13 arranged longitudinally atthe base of the walls 2c and 2d (figure 2).

it is also possible to envisage the case in which leaks close to themetal rib and taking place from under the cushions 3a and 3b areeliminated, as is described in Guienne et al. US. Pat. No. 3,482,528 bymaintaining only the supply 30 of fluid to the guidance cushions 3c and3d (figure 3). In this case the walls 2c and 2d will not be equippedwith venting orifices 13.

I claim:

1. A ground efi'ect transportation track for fluid cushion machines,having support and guiding faces therefor, the guiding faces beingformed on a rib and including active longitudinal strips which arecushion wetted upon passage of a machine and which bound on said guidingfaces adjacent inactive portions located outside normal cushion path,wherein the improvement comprises a vent duct extending within thethickness of said rib from an end located on such an inactive portion toanother end located on said track away from said support and guidingfaces thereof.

2. A track according to claim 1, wherein the said former end is locatedat the top of said rib.

3. A track according to claim 2, wherein the said rib is hollow,comprising generally parallel spaced walls which define the said ventduct between them.

4. A track according to claim 3, wherein the machine supporting part ofthe track is raised to define beneath it a space communicating with theatmosphere, the said spaced parallel walls extending through saidmachine supporting part and the said vent duct opening into this space.

5. A track according to claim 4, further comprising orifices in the saidspaced parallel walls in the region of the junction between these wallsand the machine-supporting part of the track.

1. A ground effect transportation track for fluid cushion machines,having support and guiding faces therefor, the guiding faces beingformed on a rib and including active longitudinal strips which arecushion wetted upon passage of a machine and which bound on said guidingfaces adjacent inactive portions located outside normal cushion path,wherein the improvement comprises a vent duct extending within thethickness of said rib from an end located on such an inactive portion toanother end located on said track away from said support and guidingfaces thereof.
 2. A track according to claim 1, wherein the said formerend is located at the top of said rib.
 3. A track according to claim 2,wherein the said rib is hollow, comprising generally parallel spacedwalls which define the said vent duct between them.
 4. A track accordingto claim 3, wherein the machine supporting part of the track is raisedto define beneath it a space communicating with the atmosphere, the saidspaced parallel walls extending through said machine supporting part andthe said vent duct opening into this space.
 5. A track according toclaim 4, further comprising orifices in the said spaced parallel wallsin the region of the junction between these walls and themachine-supporting part of the track.